1. Field of the Invention
The present invention relates to a brushless dc motor driver circuit capable of reducing vibration or shock noise and a method thereof, particularly to a brushless dc motor driver circuit capable of reducing vibration or shock noise and a method thereof, wherein a Time-Voltage Digital/Analog Converter outputs analog signals to drive a brushless dc motor and reduce the vibration or shock noise of the brushless dc motor.
2. Description of the Related Art
The brushless dc motor is also called the Hall motor or the DC Servo Motor, which utilizes a permanent magnet as its rotor and utilizes the Hall effect to detect the position of the rotor. As the brushless dc motor utilizes Hall sensors to determine the excitation sequence and timing, it is also called the electronic phase-switching motor. As the magnetic field (i.e. the driving torque) is applied to the rotor just at the right time, the power is saved, and the torque and efficiency of the motor is promoted. Because the offset voltage of the Hall plate and the instrumentation amplifier are usually larger than the signal detected by the Hall sensor, the traditional amplifier configurations are not suitable for the Hall sensor. Usually the chopper amplifier architecture is used in the conventional Hall motor. However, the chopper amplifier is constrained by its chopping frequency. When a brushless dc motor has a higher rotation speed, the magnetic field variation cannot be effectively reconstructed as the driving voltage for the brushless dc motor during the phase-switching process. Thus, the torque changing rate and the vibration or shock noise will be greater.
Accordingly, the present invention proposes a brushless dc motor driver circuit capable of reducing vibration or shock noise and a method thereof to overcome the abovementioned problems.